Self-assembled growth and magnetotransport investigations on strained Si/SiGe multilayers on vicinal (113)-Si surfaces

We have reported on the growth and magnetotransport properties of modulation p-doped Si_1-xGe_x quantum wells on strained multilayers of 2.5 nm Si_1-xGe_x/10 nm Si on vicinal (113) Si surfaces. Owing to the strong step-bunching properties of the (113) Si surface, both the Si_1-xGe_x and the Si layers exhibited a regular pattern of large steps. Low-temperature magnetotransport measurements revealed a hole density (6-9×10¹¹ cm^-2) independent of direction, whereas a pronounced mobility anisotropy was found. The mobility (1000-2000 cm²/Vs) was approximately two times higher along the [33-2] direction compared to a perpendicular [-110] direction. This is attributed to anisotropic hole scattering caused by anisotropic shear strain which is always present in strained layers on (113) Si. No influence of the large regular steps, whose direction is given by the direction of the substrate miscut, on the mobility was found.